Self-mode-locking in a high-power hybrid silicon nitride integrated laser.

Integrated mode-locked lasers are useful tools in microwave photonic applications as a local oscillator. In particular, hybrid integrated lasers could easily be integrated with passive processing circuits. In this Letter, we report on the self-mode-locking of a hybrid integrated laser comprising two indium phosphide gain sections and a silicon nitride feedback circuit that filters light using two ring resonators. The hybrid laser is shown to mode-lock and to have a mostly frequency-modulated field in the cavity using a stepped-heterodyne optical complex spectrum analysis. A mostly frequency modulated field output is good for high powers per line due to a more continuous emission, compared with mode-locked lasers using a saturable absorber; additionally, the filter limits the bandwidth of the comb, condensing the power to the fewer comb lines.

Silicon nitride microwave photonic circuits.

We present an overview of several microwave photonic processing functionalities based on combinations of Mach-Zehnder and ring resonator filters using the high index contrast silicon nitride (TriPleX™) waveguide technology. All functionalities are built using the same basic building blocks, namely straight waveguides, phase tuning elements and directional couplers. We recall previously shown measurements on high spurious free dynamic range microwave photonic (MWP) link, ultra-wideband pulse generation, instantaneous frequency measurements, Hilbert transformers, microwave polarization networks and demonstrate new measurements and functionalities on a 16 channel optical beamforming network and modulation format transformer as well as an outlook on future microwave photonic platform integration, which will lead to a significantly reduced footprint and thereby enables the path to commercially viable MWP systems.

Experimental training model of pancreas transplant.

UNLABELLED: Pancreas transplant (Ptx) is the gold standard for the treatment of type I diabetes, mainly when associated with renal failure. The number of Ptx is increasing worldwide, but in developing countries, such as Brazil, the number of centers is small and transplant surgeons need to practice the technique. METHODS: For this model, 21 pancreas harvestings were performed in patient corpses after death from extra-abdominal causes, without pancreatic disease and peritoneal or systemic infection. The vessels of the grafts were prepared on the backtable according to the usual practice in humans. The pancreas was implanted in the inferior vena cava and aorta of mixed breed dogs, with 10 exocrine-bladder drainage and 11 duodenum-ileal anastomosis. RESULTS: There were anastomotic strictures of the portal vein in dogs 1 and 2. There was no arterial stricture or large bleeding. None of the animals died until the revascularization of the graft. Dogs 2, 5, and 8 died during the exocrine anastomosis. The arterial flow was initially high, but at the end of the procedure there were thromboses of small arteries. CONCLUSION: The experimental surgical technique model is feasible, repeating the stages of clinical pancreatic transplantation and allowing the training of surgeons.

The Miami experience with almost 100 multivisceral transplants.

We report our experience with 98 patients who received primary multivisceral transplantations. Three eras can be distinguished based on the evolution of technique, immunosuppression, and monitoring: August 1994 to December 1997 (first era); January 1998 to December 2000 (second era); and January 2001 to present (third era). Sixteen patients were transplanted during the first era, 18 during the second era, and 64 during the third era. Fifty-three patients are alive with a median follow-up of 37.5 months (range: 1 to 116 months). The leading cause of mortality was infection (n = 17), followed by rejection (n = 6). Seven patients required retransplantation and five of them subsequently died. The estimated 3-year survival was 25% +/- 11% for era 1; 44% +/- 12% for era 2; and 58% +/- 7% for era 3. Additionally, 45.3% (29/64) of patients in the third era never developed rejection versus 23.5% (8/34) of patients in the first two eras combined. The percentage of patients who developed a moderate or severe rejection was significantly less in the third era compared with the first two eras combined, 31.6% (20/64) versus 67.6% (23/34). A comparison of the hazard rate of developing severe rejection showed a protective effect of the multivisceral graft (P = .0001). In conclusion, multivisceral transplantation is indicated for patients with short bowel syndrome and extended abdominal catastrophies. Evolution in surgical techniques, immunosuppression, and monitoring have improved patient survival, which is now similar to that of other complex solid organ transplants.

An association of lower serum citrulline levels within 30 days of acute rejection in patients following small intestine transplantation.

INTRODUCTION: In a prospective protocol we studied whether serum citrulline level within 30 days of an acute rejection was predictive of the episode. METHODS: An acute rejection episode was defined as the date of occurrence of any biopsy-proven rejection in which treatment was initiated until two successive biopsies showed no further rejection. We compared the mean citrulline level based on values determined within 30 days of the start of an acute rejection episode with the mean citrulline level measured on the same patient during a rejection-free period. Serum citrulline measurements were available immediately prior to the occurrence of rejection for 22 patients who experienced 37 episodes. RESULTS: For the 12 episodes of mild rejection, the mean serum citrulline level +/- SE (standard error) was 15.0 + 2.3 micromol/L prior to rejection and 18.8 +/- 2.4 micromol/L during the rejection-free periods. A paired t test of the mean differences was not significant (P = 17). For the 25 episodes of moderate or severe rejection, the mean serum citrulline level was 12.4 +/- 1.1 micromol/L before rejection and 18.8 +/- 2.0 micromol/L during the rejection-free periods. A paired t test of the mean difference was statistically significant (P = .002). CONCLUSIONS: Although further study of citrulline as a marker for the early detection of acute rejection episodes is needed, our hope is that its use will help to prevent some of these early episodes from evolving into full-blown moderate or severe grades of rejection.

Ten years' evaluation of potential pancreas donors in São Paulo, Brazil.

BACKGROUND: Pancreas transplantation is a treatment for advanced type 1 diabetes and offers significant improvement in quality of life. Recent advances in surgical techniques and immunosuppression regimes lead to good outcomes. However, despite significant higher rates of multiorgan donors in Brazil, pancreas transplantation seems to have remained stable. This study aimed to investigate the acceptance rate of potential pancreas donors in the past 10 years in São Paulo State. METHODS: We retrospectively evaluated potential pancreas donors characteristics and its acceptance rate in São Paulo State in the past 10 years. We divided this period into 2 eras: 1st era from January 2003 to January 2008; and 2nd era from January 2008 to January 2013. Data were obtained from São Paulo's government official website. RESULTS: During the whole period, 5,005 deceased donors of all ages were available for pancreas transplantation. According to eras, we had 1,588 donors in the 1st and 3,417 in the 2nd era. In the 2nd era, donors >49 years old were significantly more common (P < .001). Blood test abnormalities, donor comorbidities, and high dosage of vasopressors also were significantly higher in the 2nd era. Rate of graft acceptance had a significant decrease in the 2nd era, from 46.4% to 25% (P < .05). CONCLUSIONS: Despite greater organ availability, pancreas transplantations performed in São Paulo State remained stable. Rate of graft acceptance is dramatically lower in more recent years.

Home parenteral nutrition program and referral of potential candidates for intestinal and multivisceral transplantation in a single Brazilian center.

Intestinal failure is a multifaceted condition that may require high-complexity treatment and a multidisciplinary program, including home parenteral nutrition therapy (HPNT) and intestinal transplantation. In this article, we profile a Brazilian single-center experience with 128 cases of HTPN followed for the last 30 years and appraise the referral for potential intestinal and multivisceral transplantation.

Intestinal and multivisceral retransplantation results: literature review.

BACKGROUND: Intestinal/multivisceral transplantation (IT/MVT) is the gold standard treatment for patients with intestinal failure and complications related to total parenteral nutrition, gastrointestinal inoperable indolent tumors, or diffuse portal trombosis. Currently, the reported 1-year patient survival rate is around 80%, similar to other solid organ abdominal transplantations. Unfortunately, the patient survival decreases after the first year with the 5-year rate not close to 70% yet. Acute cellular rejection is the main cause of graft loss. Its early diagnosis may make it possible to improve survival of retransplantations. OBJECTIVE: To analyze the reported results published in the last 5 years by leading transplant centers to evaluate IT/MVT retransplantation results. METHODS: We performed a literature review using PubMed focusing on multivisceral and intestinal retransplantation in articles published between 2006 and 2012. In relation to the first transplantation, we analyzed demographics, imunosuppression, rejection, infection as well as graft and patient survival rates. RESULTS: Two centers reported results on intestinal and multivisceral retransplantations. Mazariegos et al reported their experience with 15 intestinal retransplantations in 14 pediatric recipients. Four patients died from posttransplant lymphoperliferative disease, severe acute cellular rejection, fungal sepsis, or bleeding from a pseudoaneurysm at a mean time of 5.7 months post-transplantation. Total parenteral nutrition was weaned at a median time of 32 days. Abu-Elmaged et al reported 47 cases with a 5-year survival of 47% for all retransplant modalities. Retransplantation with liver-contained visceral allograft achieved a 5-year survival rate of 61% compared with 16% for liver-free visceral grafts. CONCLUSION: Despite those huge improvements, some transplanted patients develop severe acute cellular rejection, culminating in graft loss and retransplantation. Repots on multivisceral and intestinal retransplantation outcomes suggest that it is a viable procedure with appropriate patient survival after primary graft loss.

Intestinal and multivisceral transplantation immunosuppression protocols--literature review.

INTRODUCTION: Currently the most used techniques for small bowel transplant are isolated intestinal transplantation, multivisceral transplantation (MVT), and modified multivisceral transplantation. One important factor is early diagnosis of acute cellular rejection (ACR). In addition, improvements in immunosuppression have recently reduced the number and enhanced treatment of ACR episodes, enabling graft recovery. OBJECTIVE: We analyzed immunosuppression protocols of leading transplantation centers in the last 5 years. METHOD: We reviewed papers published in PubMed from major multivisceral and intestinal transplantation centers from 2006 to 2010 in adult recipients. The 211 adults transplanted in seven centers were divided into three groups according to the immunosuppression protocol used: protocol 1: daclizumab induction with tacrolimus and steroid maintenance; protocol 2: alemtuzumab and tacrolimus; and protocol 3: thymoglobulin and rituximab and tacrolimus. RESULTS: Protocol 2 showed the lowest rate of ACR (34%). Protocols 1 and 3 displayed 54% and 48% ACR rates; respectively. However, protocol 1 patients developed only mild ACR, whereas those in protocols 2 and 3 developed moderate ACR in 26.3% and 11.7%, and severe ACR in 7.9% and 47% of cases, respectively. The infection rate was considerably lower in protocol 3 (7.4%). Protocols 1 and 2 showed infection rates of 62.5% and 52%, respectively. One-year patient survival rates were 70%, 79% and 81%, respectively. Three-year patient survival rates were 62%, 56%, and 78% for protocols 1, 2 and 3, respectively. CONCLUSION: Protocol 2 was the strongest immunosuppressive regimen capable of reducing ACR rates when compared with the other protocols, but the strong effect resulted in high infection rate that impacts 1-year patient survival. Protocol 3 seems to be the best available one balancing ACR and infection rates.

Effects of a diet rich in phytoestrogens on prostate-specific antigen and sex hormones in men diagnosed with prostate cancer.

OBJECTIVES: To determine the effects of diets rich in soy and linseed compared with a control diet on biochemical markers of prostate cancer in men diagnosed with prostate cancer. METHODS: Twenty-nine men diagnosed with prostate cancer and scheduled to undergo a radical prostatectomy were randomized to one of three groups: soy (high phytoestrogen), soy and linseed (high phytoestrogen), or wheat (low phytoestrogen). A bread was specially manufactured to incorporate 50 g of heat-treated (HT) soy grits or 50 g of HT soy grits and 20 g of linseed as part of the study participant's daily diet. Baseline and preoperative levels of prostate-specific antigen (PSA), free PSA, testosterone, sex hormone-binding globulin, free androgen index, and dihydrotestosterone were measured. RESULTS: Statistically significant differences were detected between the HT soy grits group and the control wheat group for the percentage of change in total PSA (-12.7% versus 40%, P = 0.02) and the percentage of change in free/total PSA ratio (27.4% versus -15.6%, P = 0.01); and between the HT soy grits group and the HT soy grits and linseed group for the percentage of change in free androgen index (16.4% versus -15.5%, P = 0.04) and the percentage of change in free/total PSA ratio (27.4% versus -10%, P = 0.007). CONCLUSIONS: The data from this study indicate that a daily diet containing four slices of a bread rich in HT soy grits favorably influences the PSA level and the free/total PSA ratio in patients with prostate cancer. This work provides some evidence to support epidemiologic studies claiming that male populations who consume high phytoestrogen diets have a reduced risk of prostate cancer development and progression.